The word Facebook appears only a few times in the text of the new Pew Internet report on “reputation management,” but it’s screamed from between the lines.

The report, released Thursday by the Pew Internet & American Life Project, is a follow-up to a 2007 report on Internet users’ “digital footprints.” Between the two studies, Facebook membership went from 12 million to 300 million. It’s now at 500 million. There’s a lot more reputation out there to manage.

Who attempts to manage it? Says the report: “Those who know more, worry more. … The more often a user searches for information about others, the more likely she is to limit access to her own personal information.”

Internet users ages 18-29 are more likely than older adults to realize what sort of personal information is out there: They’re the most active searchers of information about themselves and others. They’re also the least trusting of social networks and the most likely to limit the information about themselves available online, by changing privacy settings, untagging photos, deleting unwanted comments.

One statistic that was not broken down by age or tendency to “curate content”: “Fully 50% of Internet users agree with the following statement: ‘It bothers me that people think it’s normal to search for information about others online.’” I’d bet those that are more accepting of personal searching are also those that closely guard their own information.

But though in many ways the 18-to-29 set is the canniest controller of online presence, they’re a lot more lax about one piece of information: birthdate. (Which is required by Facebook, and which many Facebook users leave public.) Fifty-nine percent of social network users in that age group say that their birthdate is available online for others to see.

It may not affect reputation, but birthdate is a frequent entry point for identity thieves. The Pew report cites studies showing that “the vast majority of Americans (87%) can be identified with only three pieces of information: gender, ZIP code and date of birth” and that “the acquisition of a birthdate, particularly when combined with location information for younger users, can be used to successfully predict Social Security numbers.”

Go ahead and Google. Searching for personal information is a neglected professional tool, MIT digital-business fellow Michael Schrage argues in a guest blog for the Harvard Business Review. “I always Google people that I am meeting for the first time,” he says, and adds, “Almost always, the person appreciates that I … made the effort.”

So why, he asks, do people tell him they rarely search for information about clients, colleagues, bosses? Why do his students not Google him? He goes so far as to label non-searchers “lazily disrespectful.”

The post’s commenters point out what Schrage has missed (and the Pew report confirms): Googling people is seen as somewhat creepy and voyeuristic. Maybe his students aren’t lazy or disrespectful, but discreet. Rarely, outside of Jim Carrey movies, does one introduce himself to a potential employer with: “Hey, Googled you last night! That was some trip to Cancun!”